November 2, 2012
An Older Tycho
image by François Emond
With a diameter of 86 km and an estimated depth of 4.8 km, Geminus is essentially the same size as Tycho. The central peaks of Geminus are more stubby than those of Tycho, its terraces are more rounded and subdued, and it lacks rays. All of this is due to aging by seismic shaking from subsequent impacts and a steady bombardment of small meteorites that round off sharp edges. Goodacre reported that Schmidt drew two rilles on the crater's floor, but this image and others (including Clementine) show that they do not, and never did, exist.
This is a classic LPOD from June 23, 2008.
08/30/07; 02h11 UT. Dobson 16" + FFC Barlow lens + webcam Vesta Pro (B & W, raw mode) + red filter
Rükl plate 16
An earlier view
Yesterday's LPOD: Features of Interest in a Small Area
Tomorrow's LPOD: Multiphase